From 1e5c432e1029601a664454388ae366ef69618d62 Mon Sep 17 00:00:00 2001
From: Christopher Speller <crspeller@gmail.com>
Date: Mon, 25 Jun 2018 12:33:13 -0700
Subject: MM-10702 Moving plugins to use hashicorp go-plugin. (#8978)

* Moving plugins to use hashicorp go-plugin.

* Tweaks from feedback.
---
 .../github.com/hashicorp/go-plugin/grpc_server.go  | 132 +++++++++++++++++++++
 1 file changed, 132 insertions(+)
 create mode 100644 vendor/github.com/hashicorp/go-plugin/grpc_server.go

(limited to 'vendor/github.com/hashicorp/go-plugin/grpc_server.go')

diff --git a/vendor/github.com/hashicorp/go-plugin/grpc_server.go b/vendor/github.com/hashicorp/go-plugin/grpc_server.go
new file mode 100644
index 000000000..3a727393c
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-plugin/grpc_server.go
@@ -0,0 +1,132 @@
+package plugin
+
+import (
+	"bytes"
+	"crypto/tls"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials"
+	"google.golang.org/grpc/health"
+	"google.golang.org/grpc/health/grpc_health_v1"
+)
+
+// GRPCServiceName is the name of the service that the health check should
+// return as passing.
+const GRPCServiceName = "plugin"
+
+// DefaultGRPCServer can be used with the "GRPCServer" field for Server
+// as a default factory method to create a gRPC server with no extra options.
+func DefaultGRPCServer(opts []grpc.ServerOption) *grpc.Server {
+	return grpc.NewServer(opts...)
+}
+
+// GRPCServer is a ServerType implementation that serves plugins over
+// gRPC. This allows plugins to easily be written for other languages.
+//
+// The GRPCServer outputs a custom configuration as a base64-encoded
+// JSON structure represented by the GRPCServerConfig config structure.
+type GRPCServer struct {
+	// Plugins are the list of plugins to serve.
+	Plugins map[string]Plugin
+
+	// Server is the actual server that will accept connections. This
+	// will be used for plugin registration as well.
+	Server func([]grpc.ServerOption) *grpc.Server
+
+	// TLS should be the TLS configuration if available. If this is nil,
+	// the connection will not have transport security.
+	TLS *tls.Config
+
+	// DoneCh is the channel that is closed when this server has exited.
+	DoneCh chan struct{}
+
+	// Stdout/StderrLis are the readers for stdout/stderr that will be copied
+	// to the stdout/stderr connection that is output.
+	Stdout io.Reader
+	Stderr io.Reader
+
+	config GRPCServerConfig
+	server *grpc.Server
+	broker *GRPCBroker
+}
+
+// ServerProtocol impl.
+func (s *GRPCServer) Init() error {
+	// Create our server
+	var opts []grpc.ServerOption
+	if s.TLS != nil {
+		opts = append(opts, grpc.Creds(credentials.NewTLS(s.TLS)))
+	}
+	s.server = s.Server(opts)
+
+	// Register the health service
+	healthCheck := health.NewServer()
+	healthCheck.SetServingStatus(
+		GRPCServiceName, grpc_health_v1.HealthCheckResponse_SERVING)
+	grpc_health_v1.RegisterHealthServer(s.server, healthCheck)
+
+	// Register the broker service
+	brokerServer := newGRPCBrokerServer()
+	RegisterGRPCBrokerServer(s.server, brokerServer)
+	s.broker = newGRPCBroker(brokerServer, s.TLS)
+	go s.broker.Run()
+
+	// Register all our plugins onto the gRPC server.
+	for k, raw := range s.Plugins {
+		p, ok := raw.(GRPCPlugin)
+		if !ok {
+			return fmt.Errorf("%q is not a GRPC-compatible plugin", k)
+		}
+
+		if err := p.GRPCServer(s.broker, s.server); err != nil {
+			return fmt.Errorf("error registring %q: %s", k, err)
+		}
+	}
+
+	return nil
+}
+
+// Stop calls Stop on the underlying grpc.Server
+func (s *GRPCServer) Stop() {
+	s.server.Stop()
+}
+
+// GracefulStop calls GracefulStop on the underlying grpc.Server
+func (s *GRPCServer) GracefulStop() {
+	s.server.GracefulStop()
+}
+
+// Config is the GRPCServerConfig encoded as JSON then base64.
+func (s *GRPCServer) Config() string {
+	// Create a buffer that will contain our final contents
+	var buf bytes.Buffer
+
+	// Wrap the base64 encoding with JSON encoding.
+	if err := json.NewEncoder(&buf).Encode(s.config); err != nil {
+		// We panic since ths shouldn't happen under any scenario. We
+		// carefully control the structure being encoded here and it should
+		// always be successful.
+		panic(err)
+	}
+
+	return buf.String()
+}
+
+func (s *GRPCServer) Serve(lis net.Listener) {
+	// Start serving in a goroutine
+	go s.server.Serve(lis)
+
+	// Wait until graceful completion
+	<-s.DoneCh
+}
+
+// GRPCServerConfig is the extra configuration passed along for consumers
+// to facilitate using GRPC plugins.
+type GRPCServerConfig struct {
+	StdoutAddr string `json:"stdout_addr"`
+	StderrAddr string `json:"stderr_addr"`
+}
-- 
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